tomoyo: Remove "select SRCU"

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it.  Therefore, remove the "select SRCU"
Kconfig statements.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

security/tomoyo/Kconfig

@@ -6,7 +6,6 @@ config SECURITY_TOMOYO
 	select SECURITYFS
 	select SECURITY_PATH
 	select SECURITY_NETWORK
-	select SRCU
 	default n
 	help
 	  This selects TOMOYO Linux, pathname-based access control.